Photoconductive polymers of thiocyano-substituted-9-vinylcarbazoles

ABSTRACT

An electrophotographic potosensitive materials comprises a polymer containing a moiety of cyano or thiocyano substituted 9vinylcarbazole unit.

'United States Patent 11 1 Fida et al.

[ Nov. 4, 1975 PHOTOCONDUCTIVE POLYMERS OF THIOCYANO-SUBSTITUTED-9- VINYLCARBAZOLES [75] Inventors: Takeshi Fida, Chiba; Katsuhiko Nishide, Tokyo; Teruo Yamanouchi,

Fujisawa; Kikuo Kinjo, Tokyo, all of Japan [73] Assignee: Canon Kabushiki Kaisha, Tokyo,

Japan [22] Filed: July 18, 1974 21 Appl. No.: 489,530

Related US. Application Data [63] Continuation of Ser. No. 396,700, Sept. 13, 1973, abandoned, which is a continuation of Ser. No. 195,852, Nov. 4, 1971, abandoned.

[30] Foreign Application Priority Data [58] Field of Search 96/15, 1.6; 260/795 R, 260/797, 315, 88.3 R

[56] References Cited UNITED STATES PATENTS 3,287,121 11/1966 Hoegl 96/1.S 3,418,116 12/1968 Inami et ;a1...... 96/1.5 3,421,891 l/1969 lnami et :al...... 96/1.6 3,542,546 11/1970 FOX 96/1.5 3,627,524 12/1971 Kinjo et a1. 96/1.6 X

FOREIGN PATENTS OR APPLICATIONS 4,114,508 8/1966 Japan 96/15 437,592 3/1968 Japan 96/].5

Primary Examiner-Roland E. Martin, Jr. Attorney, Agent, or Firm-Fitzpatrick, Cella, Harper & Scinto ABSIRACT An electrophotographic potosensitive materials comprises a polymer containing a moiety of cyano or thiocyano substituted 9-vinylcarbazole unit.

4 Claims, No Drawings PHOTOCONDUCTIVE POLYMERS OF THIOCYANO-SUBSTITUTED-9-VINYLCAR- BOZOLES This is a continuation of application Ser. No. 396,700, filed Sept. 13, 1973, now abandoned, which is a continuation of Ser. No. l95,852, filed Nov. 4, 1971, now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to an electrophotographic photosensitive material.

2. Description of the Prior Art There have been known various organic photoconductive materials for electrophotographic photosensitive members. However, conventional organic photoconductive materials are of low sensitivity, and the sensitivity has not been improved without deteriorating the color tone of the photosensitive layer, glassy uniformity and flexibility.

Organic photoconductors of high polymer type have been also known. For example, there may be mentioned polymers having heterocyclic moiety such as carbazole ring and polymers containing polynuclear aromatic ring moiety such as naphthalene ring, anthracene ring and the like.

These organic high polymer conductors have various advantages such as transparency, light weight and filmshapeability and are expected to be used widely. Nevertheless they are not practically used since their photosensitivity IS disadvantageouslyfar lower and the physical property is not better than conventional inorganic photoconductors.

SUMMARY OF THE INVENTION According to this invention, the electrophotographic photosensitive materials comprises a polymer containmg a moiety of cyano or thiocyano substituted 9-vinylcarbazole unit having the formula:

lam-05a or -S' C EN where R is a member selected from the group consistmg of hydrogen, chloro, bromo, iodo and nitro.

An ob ect of this invention is to provide an electrophotographic photosensitive material of high sensitivity and low remaining potential when exposed.

Another object of this invention is to provide an electrophotographic photosensitive material having good physical properties.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Representative polymers having cyano substituted.

substituted poly-9-vinylcarbazole, thiocyano substituted copolymer of 9-vinylcarbazole with acrylic acid ester, methacrylic acid ester, or styrene, thiocyano substituted hologenated 9-vinylcarbazole homopolymers or copolymers.

The copolymers are prepared for the purpose of improving film-shapeability, flexibility and solubility by introducing a monomer unit suitable therefore.

When the monomer unit does not have photoconductivity, sensitivity of the resulting copolymer is generally lowered, but this lowering is compensated by cyanogenation or thiocyanation.

The mechanism by which the electrophotographic photocensitive material of the instant invention shows high sensitivity and high photoconductivity is not clear, but it is considered that the 9-vinylcarbazole ring moiety behaves as donor and cyano and thiocyano groups behave as acceptor and there occurs intramolecular charge transfer.

When the polymer of the instant invention is a copolymer containing cyanoor thiocyano substituted 9- vinylcarbazole unit, the copolymer may contain the following monomer units in addition to those as men tioned previously: 2-vinylpyridine, vinylanthracene, vinylnaphthalene, styrene, acrylonitrile, me'thyl' acrylate, ethyl acrylate, vinyl acetate, vinylidene chloride, vinyl carbazole, halogen-, nitroor amino-substituted vinylcarbazole, vinyl stearate, n'butyl acrylate, arcyloxyethyldiethylamine, vinyl cinnamate, ethylene, vinyl pyrrolidone, vinyl chloride and the like.

The copolymers of the present invention may contain two or more monomer units in addition to the cyanoor thiocyano-substituted vinylcarbazole monomer unit.

Thepolymers containing cyanoor thiocyano vinylcarbazole unit of the instant invention may be, prepared by various organic synthesis methods. Representative examples the thereof are' shown below.

l. 9-Vinylcarbazole having a halogen substituent or derivative thereof is homopolymerized or copolymerized and then reacted with a cyanide.

2. Homopolymer or copolymer of 9-vinylcarbazole or derivative thereof is halogenated by a conventional method and then reacted with a. cyanide.

It has been found that in the reactions (1) or (2) above the halogen atom particularly bromine and iodine atom present at 3--or 6-position of the carbazole nucleus is smoothyl replaced by a cyano group when the carbazole ring is treated by heating with cuprous cyanide in a non-proton polar solvent such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone and the like. The resulting percentage of replacement of halogen atom depends on kind of halogen and reaction conditions, but at an optimum condition it amounts to almost In the above reaction, gellation hardly occurs during the reaction procedure and after the end product has been obtained. I

Examples of homopolymer or copolymer of 9-vinylcarbazole or derivative thereof to which cyano or thiocyano group is to be introduced are shown below.

A. Homopolymers of 9-vinylcarbazole having a halogen substituent: I

homopolymer derived from monomers such as 3-bromo-9-vinylcarbazole, 3-iodo-9-vinylcarbazole, 3-chloro6-bromo-9-vinylcarbazole, 3, 6-diiodo-9-vinylcarbazole, 3-chloro-9-vinylcarbazole,

3 3, 6-dichloro-9-vinylcarbazole, 3-chloro-6iodo-9-vinylcarbazole and the like.

B. Copolymer of 9-vinylcarbazole having a halogen substituent:

copolymer of a monomer described (A) above with a monomer such as 2-vinylpyridine,

vinylanthracene,

vinylnaphthalene,

styrene,

acrylonitrile,

methyl acrylate,

ethyl acrylate,

vinyl acetate,

vinylidene chloride,

vinylcarbazole,

nitro substituted vinylcarbazole,

amino substituted vinylcarbazole,

halogen substituted vinylcarbazole (excluding conbinations with the same one as mentioned in A) above),

vinyl stearate,

n-butyl acrylate,

acryloxydiethylamine,

vinylcinnamate,

ethylene,

' vinylpyrrolidone,

vinylchloride, and the like.

C. Homopolymers of 9-vinylcarbazole derivative having a halogen substituent:

homopolymer derived from monomers such as 3-bromo-6-nitro-9-vinylcarbazole, 3-chloro-6-nitro-9-vinylcarbazole.

D. Copolymers of monomers described in (C) above with monomers described in (B) above (as copolymer of 9-vinylcarbazole derivative). 3. Cyano group may be introduced into homopolymer or copolymers of 9- vinylcarbazole or 9-vinylcarbazole derivative by Friedel-Crafts reaction with cyanogen bromide.

Preparation examples of cyano substituted poly-9- vinylcarbazoles are shown below.

PREPARATION EXAMPLE 1 5.0 g. of poly-9-vinylcarbazole was dissolved in 50 cc. of pyrodine and 6.6 g. of iodine was added thereto and stirred for 3 hours at 1 10 C. After cooled, the solution was poured into a large amount of methanol to precipitate the resulting polymer. The polymer was filtered, dried and purified by reprecipitating in pyridinemethanol. The polymer thus obtained was an iodinated poly-9-vinylcarbazole and contained 20.49 of iodine according to elementary analysis.

2.0 g. of the iodinated poly-9-vinylcarbazole was dissolved in 50 cc of N-methyl-2-pyrrolidone, and 0.5 g. of cuprous cyanide was added thereto and stirred at 150 C for 6 hours. After cooled, the above mixture was poured into a large amount of methanol to precipitate the polymer thus produced and the polymer thus precipitated was filtered, dried and purified by reprecipitating in pyridine-methanol to give white polymer. This white polymer is soluble in organic solvents such as tetrahydrofuran, pyridine, chlorobenzene and the like. Infrared absorption spectrum of the polymer shows absorptions at 2210 cm for cyano, and 890 cm and 805 cm for 3-position substituent of carbazole ring. Elementary analysis shows that there is contained 9.65 of nitrogen, but not any iodine. This result consists with the calculated values.

Consequently this reaction is quantitative and the re sulting polymer is mainly cyano substituted poly9- vinylcarbazole having cyano substituent at 3-position of carbazole ring which contains average 0.39 cyano groups per carbazole ring.

PREPARATION EXAMPLE 2 Following Preparation Example 1, there were prepared many iodinated po1y-9-vinylcarbazoles having a cyano substituent.

By adjusting the preparation conditions, cyano substituting degree can be controlled. General relations between preparation conditions and cyano substituting degree, are as shown below.

Degree of substitution of iodine in poly-9-vinylcarbazole can be controlled to less than 1.35 atom per vinylcarbazole ring (hereinafter, degree of substitution is designated as per vinylcarbazole ring). In the present Preparation Example, the starting material is a poly-9-vinylcarbazole having degree of iodine substitution of 0.183 to 0.706 atom. The conversion degree of iodine to cyano can amount to to depending upon selection of preparation conditions. Solvents used in preparation of iodinated poly-9-vinylcarbazole are preferably pyridine (capable of dissolving a cyano substituted polymer having up to about 0.7 cyano group per carbazole ring), tetrahydrofuran (capable of dissolving a cyano substituted polymer having up to about 0.6 cyano group per carbazole ring) and monochlorobenzene (capable of dissolving a cyano substituted polymer having up to about 0.4 cyano group per carbazole ring).

As reaction solvent, N-methylpyrrolidone is most preferable but pyridine is also preferable. The reaction temperature is 150C when N-methylpyrrolidone is used. There is obtained white polymer easily soluble in solvent. Conversion degree of cyano group is 20 to 95% and the sample is obtained by a reaction for 6-8 hours. The conversion degree amounts to as high as at 200 C for 2 hours, but there are formed colored polymer of low solubility. The amount of cuprous cyanide is preferably about up to 2 moles per 1 mole of iodine. Amount of cuprous cyanide higher than that hardly contributes to substitution degree of cyano group. The preparation conditions and elementary analysis in the present preparation examples are shown in the table below, where is percent by weight.

Iodine content CuCN/ 1 Reaction Cyanate PVCZ Solubility Analysis: in iodinated molar time CN content I content chlorotetra- No. iodine 7r PVCZ *1 ratio (hr.) *2 g "3 benzene hydrofuran ridine Color 1 1 2.67 0.183 2 6 0.140 0.043 0 0 0 White 1 2 3.43 0.287 2 4 0.231 0.056 0 0 0 White 1 3 1.82 0.327 2 6 0.298 0.009 0 0 Whitelt. brown 1 4 11.84 0.392 2 2 0.183 0.109 0 0 '0 White 1 5 4.94 0.405 2 V 4 0.323 0.082 X 0 0 White 1 6 3.91 0.405 5 4 0.339 0 0 White H I -continued I Iodinecontent CuCN/l Reaction Cyanate PVCZ Solubility Analysis: odinated molar time CN content 1 content ehlorotetra- Py No. iodine 7c VCZ:* 1 ratio (hr.) *2 *3 benzene hydrofuran ridine Color 1 7 5.10 0.416 2 3 0.331 0.085 0 White 1 8 1.97 0.416 2 8 0.384 0.032 x 0 0 White 1 9 2.18 0.610 2 6 0.374 0.036 x 0 0 White 1 10 1.78 0.610 2 8 0.580 0.030 x 0 White poly-9-vinylcarbazole of chlorine content of 4.69 7: ob- The reaction was egyected in a solve'm f Nmethy]. tained by chlorinating poly-9-viny1carbazole with sulfu- P"."; f a 9 ryl chloride was treated with 8.4 f. of iodine in a way 5 f l u e I similar to Preparation Example I). Cuprous cyanide pvc zt levy sglubililty l 5 (1.2 g.) was added thereto and reacted at 1 C for 10 po y- -viny carbazole *1 Iodine mom/carbazole ring hours. The resultmg product was treated 1n a way s1m1 *2 CN group/carbazole ring lar to Preparation Example 1 and there was obtamed *3 ldme ammlcarbamle white cyano substituted chlorinated poly-9-vinylcarbazole (elementary analysis, found: halogen, 4.61 7:; N, 8.48). This elementary analysis is consistent with PREPARATION EXAMPLE 3 5.0 g. of brominated poly-9-vinylcarbazole (bromine content, 43.28 prod'uc ed by brominating poly-9- vinylcarbazole by Wohl-Ziegler reaction or brominating po1y-9-vinylearbazole with bromine in pyridine) was dissolved in 50 cc. of pyridine, and 0.8 g. of cuprous cyanide was added thereto and reacted at l 10C for 8 hours. After cooled, the reaction solution was poured into a large amount of methanol to precipitate the resulting polymer, which was then filtered, dried, and purified by reprecipitating the polymer in pyridingmethanol to. obtain white polymer. Infrared absorption spectrum shows remarkable characteristic absorption at 2210 cm, 890 cm and 805 cm as in Preparation Example 1 and bromine content is 24.70 as the result of elementary analysis. Therefore, it is found that the polymer product is cyano substituted brominated poly- 9-vinylcarbazole having average 0.94 cyano group and average 0.89 bromine mainly at 3-position and 6-position of carbazole ring.

Reaction of brominated poly-9-vinylcarbazole with cuprous cyanide takes longer time than that of iodinated poly-9-vinylcarbazole with cuprous cyanide. Conversion degree of bromo substituent to cyano is lower than that of iodo substituent to cyano. The other example is shown below.

calculated values of halogen and nitrogen in case where all iodine are replaced by cyano group.

This result of elementary analysis indicates that average degrees of cyano and chlorine per carbazole ring were 0.25 and 0.27, respectively.

PREPARATION EXAMPLE 5 5.0 g of iodinated poly-9-vinylcarbazole (iodine content, 20.49 7c) shown in Preparation Example 1 was dissolved in 125 cc. of N-methyl-2-pyrrolidone, and 0.80 g. of cuprous cyanide was added thereto and stirred at 150 C for 8 hours followed by treating in a way similar to Preparation Example 1 to produce white polymer soluble in organic solvents. The infrared absorption spectrum shows characteristic absorption at 2210 cm for cyano and characteristic absorptions at 890 and 805 cm for 3-position substituent in carbazole ring. Elementary analysis shows 6.80 7c of iodine content. These data indicate that the resulting polymer is mainly cyano substituted iodinated poly-9-vinylcarbazole having average 0.28 cyano groups and 0.12 iodine at 3-position.

Preparation of polymers containing cyano substituted 9-vinylearbazole moiety may be carried out by cyanogenation of 9-vinylcarbazole or 9-viny1carbazole derivative and then polymerizing the cyanogenated Feed N-methyl pyrrolidone ml.

Br content in brominated poly-9- vinylcarbazole (atom/carbazole ring) Brominated poly-9- vinylcarbazole g.

CuCN/ Br molar ratio Reaction condition Reaction Reaction temperature Time "C hr Pyridine easily soluble soluble Cyano substituted poly-9-vinylcarbazole Br content (atom /carbazole ring) benzene Color slightly brown PREPARATION EXAMPLE 4 In cc. of pyridine was added 5.0 g. of chlorinated iodinated poly-9-vinylcarbazole (chlorine content, 4.07 iodine content, 13.33 10 g. of chlorinated one.

PREPARATION EXAMPLE 6 3.2 g. of 3-iodo-9-vinylcarbazole (mp. 194C. dee., produred by iodination of 9-B-chloroethylcarbazole and dehydration with potassium hydroxide) was dissolved in 50 cc. of N-methyl-Z-pyrrolidone, and 2.0 g. of Cu CN was added thereto and a small amount of hydroquinone was added and heated in an atmosphere of nitrogen at 150 C with stirring. The reaction mixture was poured into water, filtered, washed with water. dried and recrystallized three times to give 1.5 g. of 3- cyano-9-vinylcarbazole.

Analysis: Found N, 11.5 Calcd. N, 12.9 70.

0.5 g. of the resulting 3-cyano-9 vinylcarbazole and 1.0g. of 9-vinylcarbazole were placed in a polymerization tube and azobisisobutyronitrile was added and heated at 80C for 8 hoursin nitrogen atmosphere. The polymer was dissolved in tetrahydrofuran and precipitated in methanol. White polymer easily soluble in tetrahydrofuran was obtained. The resulting polymer contains about 31 7c of 3-cyano-9-viny1carbazole.

Thiocyanated polymer may be prepared, for example, as follows. 1

1. A process for making a substitution of thioeyano group to poly-9-vinylcarbazole or copolymer of 9- vinylcarbazole;

2. A process for thioeyanating halogenated 9-vinylcarbazole homopolymer or copolymer; and

3. A process for. halogenating homopolymer or copolymer of thiocyanated 9-vinylcarbazo1e.

The thioeyanation reaction may be carried out by methods described in Organic Reactions, Vol. 3, page 240 and the following pages (edited by R. Adams) or modified method thereof. There may be mentioned a. a process for adding a solution of free thiocyanogen in benzene, chlorobenzene, chloroform or methylene chloride to a solution of 9-vinylcarbazole ploymer; and

b. a process for making a reaction by forming thiocyanogen electrobytically of chemically (e.g. alkali metal thiocyanate and halogen). Some poly-9-viny1carbazoles highly substituted with thioeyano group are insoluble in benzene and monochlorobenzene and in this case it is advatageous to effect the reaction in tetrahydrofuran and dioxane. Further, the above-mentioned homopolymer of copolymer in (A)(D)'may be thiocyanated. Thiocyanat ed 9-vinylcarbazole or 9-vinylcarbazole derivative may be polymerized.

In the following there are described preparation Examples of thiocyanated 9-vinylcarbazole homopolymer and copolymer.

PREPARATION EXAMPLE 7 Poly-9-vinylcarbazo1e (3.9 g.) was dissolved in 180 ml. of monochlorobenzene, and a solution of thiocyanogen (obtained from lead thiocyanate and equiv- Amount of Reaction thiocyanogen temperature Yield Polymer (I) 0.58 g. A C 4.1 gr. (2) 1.16 g. 20C 4.4 gr.

Elementary analysis of the resulting polymer is shown below.

Polymer (l) 8.24 7: 3.85 7( easily soluble in monochlorobenzene (2) 9.50 7.18

PREPARATION EXAMPLE 8 Cupric thiocyanate 2.0 g. (obtained by adding potassium thiocyanate to an aqueous solution of cupric sulfate, filtering the resulting precipitate and washed with ethanol and then ether) was suspended in asolution of 3.9 g of poly-9-viny1carbazole in 180 ml. of monochlorobenzene and 25 ml. of glacial acetic acid and stirred at 3050C. After the black cupric thiocyanate becomes almost white, the reaction liquid is subjected to centrifugal treatment to remove insoluble matters and then poured into methanol to precipitate polymer, filtered, washed with methanol and dried under reduced pressure. Analysis of the resulting polymer: Found: N, 9.50; S, 7.02

PREPARATION EXAMPLE 9 10 g. of 9-vinylcarbazole-ethyl acrylate copolymer (9-vinylcarbazole, 71 mole was dissolved in 200 ml. of monochlorobenzene and 20 ml. of pyridine and 40 ml. of benzene containing 2.5 g. of thiocyanogen was added dropwise at 10C with stirring. Aftercompletion of the addition, the reaction was carried out further for 2 hours at the same temperature and the reaction liquid was poured into a large amount of methanol to precipitate the copolymer. The copolymer was washed with methanol and dried under vacuum.

Analysis: Found: N, 7.92 S, 6.05

Following the above preparation procedure except for using 9-vinylcarbazole-styrene copolymer (9-vinylcarbazole, mole in place of 9-vinylcarbazoleethyl acrylate copolymer, there was obtained thiocyanated 9-vinylcarbazole-styrene copolymer.

Analysis: N, 9.30 S, 7.41

PREPARATION EXAMPLE 10 4g. of po1y-9-vinylcarbazole was dissolved in 200 ml. of dry methylene chloride, and 5 ml. of methylene chloride containing 1.4 g. of sulfuryl chloride was added dropwise at 0C. Then, the reaction was effected for 3 hours at 20 C and the reaction mixture was poured into a large amount of methanol and the polymer thus precipitated was filtered and dried. Yield 4.3 g.

Analysis: Cl, 8.38 N, 6.40

The chlorinated poly-9-vinylcarbazole (21 g.) thus obtained was dissolved in 50 ml. of monochlorobenzene and 5ml. of benzene containing 0.6 g. of thiocyanogen was added dropwise with stirring at 10C.

After completion of addition, the stirring was continued for further 2 hours at the same temperature and the reaction mixture was poured into a large amount of methanol.

The polymer product thus precipitated was collected and purified by recrystallizing in monochlorobenzenemethanol. Analysis: N, 8.64 Cl, 7.39 S, 6.72

The polymers as obtained above may be made into electrophotographic photosensitive member, for examvple, by coating a solution of the polymer on a conductive support followed by drying, or melt-coating the polymer on a conductive support, or forming a self-supporting polymer film by melt-extruding or evaporating a solvent from the polymer solution.

The polymer may be used as electrophotographic photosensitive member in a form of self-supporting film or textile or a thin film on a conductive support. For example, the polymer solution is coated on a glass plate, dried and then film is peeled off and the polymer melt is oxtruded through a nozzle to form fiber and then woven, or the polymer solution was coated on a conductive support.

To the polymer there may be added additives for adjusting photographic characteristicssuch as sensitizer and additives for adjusting physical properties such as plasticizer and opaque-rendering agent.

As sensitizers, there may be mentioned, for example, Lewis acid sensitizers, polynitro compounds such as l,

'3, S-trinitrobenzene, picric acid, S-nitroacenaphthene and 2, 4, 7-trinitrofluorenone; carboxylic acid such as acetic acid, trifluoroacetic acid, trichloroacetic acid, and salicylic acid; sulfonic acid such as benzene sulfonic acid and p-toluene sulfonic acid; sulfonic acid chloride such as p-toluene sulfonic acid chloride; and optical sensitizers such as Crystal Violet, Malachite Green, Methylene Blue, Brilliant Green, and Quiniza- As plasticizers, there may be mentioned dibutyl phthalate, dioctyl phthalate, tricresyl phosphate and chlorinated polyphenyl.

Organic photoconductive are usually used together with a dye sensitizer or Lewis acid sensitizer since even the highest sensitive organic photoconductive materials are still fairly less sensitive than inorganic photoconductive materials.

The organic photoconductive materials of this invention are also excellent in light decay characteristics and photosensitivity, and it is preferable to use practically them together with various dye sensitizers and Lewis acid.

One of the most effective sensitization method for the organic photoconductive material of the present invention is free radical sensitization. Free radical sensitization may be carried out as shown below. To the organic photoconductive material of the present invention is added a free radical former in an amount of about 1-30 by weight on the basis of the organic photoconductive polymer and radiation such as ultraviolet ray or color light is applied thereto for from several minutes to several tens minutes, and the resulting sensitivity is comparable to color-sensitized zinc oxide.

Representative examples of free radical former are polyhalogen compounds such as CBr Cl CHI C Cl CBrCl CCl CHBr Cl-lCl C Br C HBr C l-l CBr ClBr ClCl CHlCl CHlBr CBrCl CHB Cl a, a, a-trichlorotoluene, a, a, a-tribromoacetophenone and the like.

It is appropriate for further sensitization to carry out free radical sensitization in the presence of sensitizers as shown below.

Leuco base or carbinol base of triphenylmethane dye such as leuco malachite grren,

leuco crystal violet,

leuco methyl violet,

leuco opal blue, and

carbinol malachite green.

Styryl dye base such as 4--(4-dimethylaminophenyl- 1,3-butadienyl) quinoline, 4-p-dimethylaminostyryl quinoline, Z-p-dimethylaminostyryl quinoline, 2-(4- dimethlaminophenyl-1,3-butadienyl) quinoline, and Z-p-dimethylstyrylbenzothiazole.

Cyanine dye base such as 2-[3-( l-ethyl-2.( 1H)-, quinolylidenel] propenyl quinoline, 2-[2-methyl-3-(3- ethyl -2(3H)-benzothiazolyllidene) propenyl]benzathiazole, and 4-[(-ethyl-2 (lH)-quinolylidene )methyllquinoline.

Merocyanine dye base such as 3-ethyl-5-[(3-ethyl-2 (3H )-benzoxazolylidene] shodanine, l-ethyl-3-[ 3- ethyl-2( 3H j-benzoxazolylidene ]oxyindole, and 4-[ 3- ethyl-2(3H)-ben2oxazolylidene]-3-phenyl-5-(4H)- isooxazolone.

Secondaryor tertiary arylamines such as diphenylanine, N-methylamine, N, N-dimethylaniline, N- ethylaniline, N, N-diethylaniline, phenyl-a-naphthylamine, phenyl fimaphthylamine, triphenylamine, and Nmethyldiph.enylamine, N-benzylaniline.

Carbazoles such as carbazole, N-ethylcarbazole, N- methylcarbazole, N-phenylcarbazole, N-benzylcarbazole, N-vinylcarbazole, 3,6-dibromo-N-vinylcarbazole, and 3- chloro-N-ethylcarbazole.

lndoles such as indole, Z-rnethylindole, l, Z-dimethylindole, l-phenylindole, 4-chloroindole, and N- vinylindole.

Free radical sensitization may be carried out not only in liquid phase, but also in solid phase, for example, irradiating a solid photosensitive film.

The electrophotographic photosensitive material may be used for producing image by using various known meansconcerning charging and development such as corona discharge, magnet brush development, and electrophoresis development.

The following examples are given for illustrating the present invention, but by no means for restricting the present invention.

EXAMPLE 1 PolyQ-vinylcarbazole (luvican M-l70. trade name. supplied by BASF) (as control) or cyanogenated poly-9-vinylcarbazole of nitrogen content as shown in (1H5) of a table below 2.0 g. Chlorobenzene 40 ml. Crystal Violet 2.0 mg

The resulting photosensitive plate was mounted on a ratary electrometer to charge negatively and exposed to tungsten lamp. Irradiation time of period was measured at one-third decay and one-tenth decay of potential and reciprocal of the value of irradiation time of period was designated as sensitivity. The sensitiv- 1 1 ity thus defined for various samples is listed in the table below. Initial potential when irradiation starts was about 500 volt for each sample.

nide in a way similar to Preparation Example 1 and thosein (4) and above were prepared by reacting a brominated poly-9-vinylcarbazole with a sufficient amount of cuprous cyanide in a way similar to Preparatlon Example 3.

EXAMPLE 2 Polymer of No. l to No. 10 in Preparation Example 2 Crystal Violet 2.4.7-Trinitrofluorenone Diphenyl chloride Chlorohenzene 5 mg. 2 mg. 0.5 g cc.

The above formulation was applied to an art paper in an amount that the dried coating is 8 microns thick to produce a photosensitive paper. This was charged in a dark place and exposed to a light image formed by a photographic enlarger equipped with a 500 W tungsten lamp through a positive microfilm original. The resulting latent image was developed with liquid developer to give good positive images. Optimum exposure was 300 lux.second.

EXAMPLE 3 5 cyanogenated polymer as listed in (1) in a table shown below Carbon tetrabromide 9 Vinylcarbazole Chlorobenzene 2.0 g. 100 mg. 180 mg A solution containing above ingredients was placed in an Erlenmyer flask of hard glass and was subjected to photochemical treatment with stirring for 5 minutes by a 100 W high pressure mercury lamp at a distance of 10 cm. Then, 2mg. of 2, 4, 7-trinitrofluorenone was added to the reaction liquid to form a photosensitive liquid. The resulting photosensitive liquid was coated on a high grade paper having a polyvinylalcohol layer on the surface to form a coating of 8p. thick (after dried). The photosensitive paper thus obtained was coronacharged at a dark place and a light image was projected thereonto by using a photographic enlarger equipped with a 500 W tungsten lamp through a positive microfilm. The resulting electrostatic latent image was developed by using a liquid developer to form positive im- 12 ages. Exposure amount required for obtaining sharp and clear positive images is described as optimum exposure for cyanogenatedjpolymers (1)-(4) in a table below. q

I Nitrogen Optimum I content exposure Cyanogenated polymers (lux. sec) 1 Cyariogenated poly-9-vinyl carbazole 8.51 150 (2) Cyanogenated poly-9-vinyl- 'carbaz ole (obtained by Preparation Example 1) 9.60 130 (3) Cyanogenated poly-9-vinyl carbazole l 1.89 120 (4) Cyanogenated-chlorinated poly-9-vinylcarbazole (obtained by Preparation Example 4) 8.36

Cyanogenated poly-9-vinylcarbazoles in (1) and (3) were prepared in a way similar to Preparation Example EXAMPLE 4 A sand-blasted aluminum plate was defatted with etheralcohol and coated with a liquid of the following composition by using a rotary coater toform a coating of 8 microns thick (after dried) and then dried with warm wind.

Poly-9-vinylcarbazole (Luvican M-170) (control) or photoconductive polymer produced by Preparation Example 7 or 8 2.0 g. Tetrahydrofuran 40 mlr 2,4,7-trinitro'fluorenone 1.0 mg.

The resulting photosensitive plate was mounted on a rotary electrometer to charge negatively and exposed to tungsten lamp. Irradiation time of period was measured at one-third decay and one-tenth decay of potential, and reciprocal of the value of irradiation time period was designated as sensitivity. The sensitivity thus defined for various samples is listed in the table below. Initial potential when irradiation starts was about 500 volt for each sample.

Thiocyanated poly-9- vinylcarbazole, content Sensitivity of sulfur 1/3 decay 1/10 decay 3.85 2.2 2.6 7.18 5.3 5.9 Poly-9-vinylcarbazole (control) 1.0 1.0

EXAMPLE 5 styrene copolymeras prepared in preparation Example.

9 in 40 ml. of monochlorobenzene, adding mg. of carbon tetrabromide and 2 mg. of triphenylbismuthine 13 thereto, irradiating with a 100 W high pressure mercury lamp at a distance of 10 cm. for 5 minutes to cause photochemical reaction, and then adding 5 mg. of 2, 4, 7-trinitrofluorenone thereto.

The resulting photosensitive paper was coronacharged in a dark place and exposed to a light image formed by a photographic enlarger equipped with a 500 W tungsten lamp through a positive microfilm original. The electrostatic image thus formed were developed with a liquid developer to obtain positive images of high contrast. Optimum exposure was 155 lux.- second for the fonner cyanogenated copolymer and 110 lux.second for the latter cyanogenated copolymer. Optimum exposure for the corresponding copolymer not cyanogenated was 465 lux.second and 310 lux.- second, respectively.

EXAMPLE 6 Thiocyanated polymer 2 g. Carbon tetrabromide I mg. 9-Vinylcarbazole 50 mg. Triphenylhismuthine 2 mg. Monochlorobenzenc 40 ml.

Optimum Thiocyanated polymer exposure Thiocyanated poly-9-vinylcarbazole; sulfur content 3.85 7:

Thiocyanated copolymer produced by Preparation Example 3 Thiocyanated polymer produced by Preparation Example 4 l05 lux.second I60 lux.second 9O lux.second Polymers which sulfur content is low, for example, sulfure content is 3.85 gave satisfactory result even when triphenylbismuthine was removed from the above formulation.

We claim:

14 l. Electrophotographic photosensitive material which consists essentially of a polymer selected from the group consisting of (l) homopolymers of a thiocyano-substituted9-vinylcarbazole unit represented by the formula:

- ca CH2 and (2) copolymers of said thiocyano-substituted9- vinylcarbazole with at least one monomer copolymerizable therewith.

2. The electrophotographic photosensitive material of claim I wherein said polymer is said copolymer (2) and said monomer is selected from the group consisting of an acrylic acid ester, 21 methacrylic acid ester and styrene.

3. Electrophotographic photosensitive material which consists essentially of a polymer selected from the group consisting of (l) homopolymers of a thiocyano-substituted9-vinylcarbazole unit represented by the formula:

wherein R is H, Cl, Br or I and wherein said homopolymer contains both monomer units where R is H and monomer units where R is Cl, Br or I; and (2) copolymers of said thiocyano-substituted-9-vinylcarbazole with at least one monomer copolymerizable therewith.

4. The electrophotographic photosensitive material of claim 3 wherein said polymer is said copolymer (2) and said monomer is selected from the group consisting of an acrylic acid ester, a methacrylic acid ester and styrene.

UNI'IED S'IA'IES W\ 'll-JN'1 OFFICE CERTIFICATE OF CGRIIECTION Patent {qr/ 4R9 Dated November 4. 1975 Inventor) TAKESHI EIDA, ET AL Page 1 of 2 o It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the cover page, between item [54] and [73] on the left hand column:

[75] Inventors: TAKESHI FIDA" should read -TAKESHI EID A- On the cover page, at [57] Abstract, the word "pbto se i tive" should read -photosensitive-- I Column 2, line 47, "smoothyl" should read smoothly Columns 3 and 4, in the Table, and Columns 5 and 6, in

the Table, "Cyanate" should read Cyanated Column 5 and 6 in the Table, underthe heading CN content #2, "0.374" should. read -9.574

In the Table at the bottom of Column 3 and 4, under theneading "chlorobenzene" third and last lines, insert A In the Table at the top of Columns 5 and 6, under the heading "chlorobenzene first line and under the healing "Solubility *etrahydrofuran", last line, insert A Column 5, line 14 :soluble" should read A asoluble Z Column 7 line 55 'therto" should read -thereto'- UNITED S'IA'IES lA'll-JN'I ()FFKIE CERTIFICATE OF CORRECTION ovember 4 1975 Patent x0. 3,917,482 Dated Inventofls) TAKESHI EIDA, ET AL g .2 0f 2 It is certified that error appears in the above-identified patent and that said Letters Pa tent are hereby corrected as shown below:

Column 9, line 16, "oxtruded" should read "extruded-- Column 10, line 1 "gr ren" should nead -green- Column 10, line 12 delete immediately after qu'inolylidene) Column 10, line 49 and 64, r'a1 :ary" shouldfread *-rot ary Column 12, line 63, "liquiejd e h ould read li uid Column 13 line 47, "sulfure'-' should read --sulfur Column 10 line l 2 insertimmediately after.

propenyl".

Signed and Scaled this A ttest:

RUTH C. MASON C. MARSH Altmting Offi ALL DANN nmmisxinm'r uflarel'zls and Trademarks 

1. ELECTROPHOTOGRAPHIC PHOTOSENSITIVE MATERIAL WHICH CONSISTS ESSENTIALLY OF A POLYMER SELECTED FROM THE GROUP CONSISTING OF (2)HOMOPOLYMERS OF A THIOCYANO-SUBSTITUTED-VINYLCARBAZOLE UNIT REPRESENTED BY THE FORMULA:
 2. The electrophotographic photosensitive material of claim 1 wherein said polymEr is said copolymer (2) and said monomer is selected from the group consisting of an acrylic acid ester, a methacrylic acid ester and styrene.
 3. Electrophotographic photosensitive material which consists essentially of a polymer selected from the group consisting of (1) homopolymers of a thiocyano-substituted9-vinylcarbazole unit represented by the formula:
 4. The electrophotographic photosensitive material of claim 3 wherein said polymer is said copolymer (2) and said monomer is selected from the group consisting of an acrylic acid ester, a methacrylic acid ester and styrene. 